Objective  To optimize the preparation parameters of the new silk birth-canal microecology transporter (BMT) for transferring the symbiotic bacteria of the birth canal efficiently.

  Methods  Birth canal microbial samples of 30 full term pregnant women at admission were collected as the control group (NC, n=30). The experimental group included 18 pregnant women terminated by Cesarean section, who were divided into 6 sub-groups （M1-M6, n=3) to complete the transfer tests of the birth-canal microecology. The new silk BMT was processed in the sterile liquid of the different osmotic pressure with the different immersion depth, and was placed in the vagina of the pregnant women for 1 h before sealed. All extracted DNA specimens were amplified in the V3-V4 region of the 16S rDNA, and were sequenced by Illumina Hiseq2500. Microbial diversity analysis was performed by Mothur, QIIME, Lefse and Metastat. Welch’s t-test and Anosim nonparametric test were used to compare the difference between groups.

  Results  The new silk BMT with 70% immersion depth could be fully covered by the solution, and had good solution preserving and adhesion. The subjects had no foreign body sensation with satisfied experience. Both of the microbes on the new BMT and the control group were lactobacillus as the dominant bacteria genus. The microbial diversity and bacteria constitution in the new BMT was similar to the control group in the condition of 0.45% NaCl solution and 70% immersion depth, and there was no significant difference between the two groups (P>0.05).

  Conclusion  The new silk BMT can transfer the symbiotic microbes of the birth canal efficiently, and the optimal preparation parameters were 0.45% hypotonic saline solution and 70% immersion depth.